changing from number to date

thanks sir. i forgot to insert the pick date
:local Date [/system clock get date]
:global num2month do={ :return [:pick "REXJANFEBMARAPRMAYJUNJULAGOSEPOCTNOVDEC" [:pick $Date 0 3]+1)] ($13) (($13)+3)] }
:log info [$num2month]

today is JUN but i need to get the JUL